This invention relates to zoom lenses for cine cameras, and more particularly to improvements over applicant's prior U.S. Pat. No. 4,017,161.
The above-identified patent describes a compact zoom lens having a zoom ratio in order of 1:5 with an F-number (aperture ratio) of 1:1.4. For a faster zoom lens having the same order of zoom ratio, a decrease in F-number down to 1:1.2 increases the various aberrations. To avoid this, it is necessary to increase the lens physical length. On the other hand, the majority of users strongly demand minimization of the bulk and size of zoom lenses. Therefore, without causing the physical length to be increased the lens' F -number must be decreased. This leads to deterioration of its spherical aberration and longitudinal and lateral chromatic aberrations. Therefore, the present invention should correct these aberrations by imparting modifications into the lenses of the fourth group or relay lens in the zoom lens described in the above-identified patent.